Growing interest in hair health has increased the demand for safe and effective hair growth agents. Keratin, a structural protein abundant in hair, skin, and nails, is essential for maintaining hair integrity and resilience. This study evaluated the effects of orally administered hydrolyzed keratin peptide on hair growth in male and female C57BL/6 mice and its cellular impact on human follicle dermal papilla cells (HFDPCs) and HaCaT keratinocytes. Oral administration of hydrolyzed keratin peptide promoted the telogen-to-anagen transition and increased expression of proliferation markers (β-catenin, cyclin D1, and proliferating cell nuclear antigen [PCNA]) in both sexes, while upregulating growth factors and antioxidant enzymes in male mice. In vitro, hydrolyzed keratin peptide enhanced HFDPC proliferation by activating β-catenin and improving cellular antioxidant capacity in both HaCaT keratinocytes and HFDPCs. These findings suggest that hydrolyzed keratin peptides are a promising functional food ingredient for promoting hair health through both proliferative and antioxidant mechanisms.
ParkAM, KhanS, RawnsleyJ. Hair biology: Growth and pigmentation. Facial Plast Surg Clin North Am.2018;26(4):415–424.
2.
BuffoliB, RinaldiF, LabancaM, et al.The human hair: From anatomy to physiology. Int J Dermatol2014;53(3):331–341.
3.
O’ConnorK, GoldbergLJ. Nutrition and hair. Clin Dermatol2021;39(5):809–818.
4.
Piérard-FranchimontC, PiérardGE. Hair and their environment. Rev Med Liege2015;70(2):70–72.
5.
YorkK, MeahN, BhoyrulB, et al.A review of the treatment of male pattern hair loss. Expert Opin Pharmacother2020;21(5):603–612.
6.
GuarnieriG, Bertagna De MarchiL, MarconA, et al.Relationship between hair shedding and systemic inflammation in COVID-19 pneumonia. Ann Med2022;54(1):869–874.
7.
ConradF, et al.Substantial sex-dependent differences in the response of human scalp hair follicles to estrogen stimulation in vitro advocate gender-tailored management of female versus male pattern balding. J Investig Dermatol Symp Proc2005;10(3):243–246.
8.
FuH. Research trends and hotspots in female pattern hair loss: A bibliometric study. J Cosmet Dermatol2025;24(8):e70369.
9.
LeeSW, JuhaszM, MobasherP, et al.A systematic review of topical finasteride in the treatment of androgenetic alopecia in men and women. J Drugs Dermatol2018;17(4):457–463.
10.
AdilA, GodwinM. The effectiveness of treatments for androgenetic alopecia: A systematic review and meta-analysis. J Am Acad Dermatol2017;77(1):136–141.e5.
11.
RogersNE, AvramMR. Medical treatments for male and female pattern hair loss. J Am Acad Dermatol2008;59(4):547–566.
12.
JankovicSM, JankovicSV. The control of hair growth. Dermatol Online J1998;4(1):2.
13.
DhariwalaMY, RavikumarP. An overview of herbal alternatives in androgenetic alopecia. J Cosmet Dermatol2019;18(4):966–975.
14.
IwabuchiT, OguraK, HagiwaraK, et al.Ginsenosides in Panax ginseng extract promote anagen transition by suppressing BMP4 expression and stimulate human hair growth by promoting follicle-cell proliferation. Biol Pharm Bull2024;47(1):240–244.
15.
HeY, LiW, ZhengZ, et al.Inhibition of protein arginine methyltransferase 6 reduces reactive oxygen species production and attenuates aminoglycoside- and cisplatin-induced hair cell death. Theranostics2020;10(1):133–150.
16.
GentileP, GarcovichS. Advances in regenerative stem cell therapy in androgenic alopecia and hair loss: Wnt pathway, growth-factor, and mesenchymal stem cell signaling impact analysis. Cells2019;8(5):466.
17.
MauriceMM, AngersS. Mechanistic insights into Wnt–β-catenin pathway activation and signal transduction. Nat Rev Mol Cell Biol2025;26(5):371–388.
18.
ZhangW, FanY. Structure of Keratin. Methods Mol Biol2021;2347:41–53.
19.
GuLH, CoulombePA. Keratin function in skin epithelia: A broadening palette with surprising shades. Curr Opin Cell Biol2007;19(1):13–23.
20.
ThorhaugeKH, ThieleM, DetlefsenS, et al.Serum keratin-18 detects hepatic inflammation and predicts progression in compensated alcohol-associated liver disease. Hepatol Commun2022;6(12):3421–3432.
21.
PowellBC, RogersGE. The role of keratin proteins and their genes in the growth, structure and properties of hair. EXS1997;78:59–148.
22.
WangZ, XiaoN, GuoS, et al.Unlocking the potential of keratin: A comprehensive exploration from extraction and structural properties to cross-disciplinary applications. J Agric Food Chem2025;73(2):1014–1037.
23.
ChenZ, CaiM, WangY, et al.Autocrine ECM molecules establish MSC quiescence during incisor development by disrupting WNT ligand trafficking. Nat Commun2025;16(1):10676.
24.
VirgilioN, SchönC, MödingerY, et al.Absorption of bioactive peptides following collagen hydrolysate intake: A randomized, double-blind crossover study in healthy individuals. Front Nutr2024;11:1416643.
25.
HwangSB, ParkHJ, LeeBH. Hair-growth-promoting effects of the fish collagen peptide in human dermal papilla cells and C57BL/6 mice modulating Wnt/beta-catenin and BMP signaling pathways. Int J Mol Sci2022;23(19):11904.
26.
KimY, LeeJO, LeeJM, et al.Low molecular weight collagen peptide (LMWCP) promotes hair growth by activating the Wnt/GSK-3β/β-catenin signaling pathway. J Microbiol Biotechnol2024;34(1):17–28.
27.
ParkKS, ParkDH. Comparison of Saccharina japonica–Undaria pinnatifida mixture and Minoxidil on hair growth promoting effect in mice. Arch Plast Surg2016;43(6):498–505.
28.
KimY, YouSH, YoonD, et al.Pea sprout extract promotes hair follicle regeneration via anagen phase prolongation and dual modulation of oxidative and inflammatory signaling. J Microbiol Biotechnol2025;35:e2508011.
29.
ZhangY, NiC, HuangY, et al.Hair growth-promoting effect of resveratrol in mice, human hair follicles and dermal papilla cells. Clin Cosmet Investig Dermatol2021;14:1805–1814.
30.
Müller-RöverS, HandjiskiB, van der VeenC, et al.A comprehensive guide for the accurate classification of murine hair follicles in distinct hair cycle stages. J Invest Dermatol2001;117(1):3–15.
31.
WangW-H, RamosR, TaiK-Y, et al.Studying hair growth cycle and its effects on mouse skin. J Invest Dermatol2023;143(9):1638–1645.
32.
OzawaA, ImadaM, HataA, et al.Differences in hair coat condition between female and male mice occur through testicular-derived factors and are affected by the presence of another mouse. PLoS One2025;20(6):e0324993.
33.
OhnemusU, UenalanM, InzunzaJ, et al.The hair follicle as an estrogen target and source. Endocr Rev2006;27(6):677–706.
34.
JinGR, ZhangYL, YapJ, et al.Hair growth potential of Salvia plebeia extract and its associated mechanisms. Pharm Biol2020;58(1):400–409.
35.
ParkHJ, ZhangN, ParkDK. Topical application of Polygonum multiflorum extract induces hair growth of resting hair follicles through upregulating Shh and beta-catenin expression in C57BL/6 mice. J Ethnopharmacol2011;135(2):369–375.
36.
RamosPM, MiotHA. Female pattern hair loss: A clinical and pathophysiological review. An Bras Dermatol2015;90(4):529–543.
37.
ParkG-H, ParkK-y, ChoH-I, et al.Red ginseng extract promotes the hair growth in cultured human hair follicles. J Med Food2015;18(3):354–362.
38.
KimY, LeeJM, JangYN, et al.Irisin promotes hair growth and hair cycle transition by activating the GSK-3beta/beta-catenin pathway. Exp Dermatol2024;33(8):e15155.
39.
ChengK, LinJ, WuM, et al.Berberine promotes hair growth by targeting Axin2 and activating Wnt/beta-catenin pathway. Phytomedicine2025;141:156669.
40.
PausR, CotsarelisG. The biology of hair follicles. N Engl J Med1999;341(7):491–497.
41.
ChiW, WuE, MorganBA. Dermal papilla cell number specifies hair size, shape and cycling and its reduction causes follicular decline. Development2013;140(8):1676–1683.
42.
DriskellRR, ClavelC, RendlM, et al.Hair follicle dermal papilla cells at a glance. J Cell Sci2011;124(Pt 8):1179–1182.
43.
LiT, ZhangG, ZhouX, et al.Cedrol in ginger (Zingiber officinale) as a promising hair growth drug: The effects of oral and external administration on hair regeneration and its mechanism. Bioorg Chem2024;151:107709.
44.
ZhuHL, GaoYH, YangJQ, et al.Serenoa repens extracts promote hair regeneration and repair of hair loss mouse models by activating TGF-beta and mitochondrial signaling pathway. Eur Rev Med Pharmacol Sci.2018;22(12):4000–4008.
